Methods of inhibiting ethylene responses in plants using dicyclopropene compounds

ABSTRACT

Methods of applying dicyclopropene compounds and compositions thereof to block ethylene receptors in plants are disclosed. Methods include applying to the plant an effective ethylene response-inhibiting amount of a dicyclopropene compound or composition thereof. Dicyclopropene compounds, enantiomers, stereoisomers or salts thereof are also provided.

RELATED APPLICATION DATA

This application is a divisional of U.S. patent application Ser. No.12/138,500, filed on Jun. 13, 2008, now allowed, which claims thebenefit of U.S. Provisional Application Ser. No. 60/945,782, filed onJun. 22, 2007, and U.S. Provisional Application Serial No. filed on60/950,645, filed on Jul. 19, 2007. The disclosure of each applicationis incorporated by reference herein in its entirety.

STATEMENT OF GOVERNMENT SUPPORT

Aspects of this research are supported by the Binational AgriculturalResearch and Development Fund (BARD) under grant number US-IS-3493-02CR.The U.S. Government has certain rights to this invention.

FIELD OF THE INVENTION

The present invention generally relates to methods of blocking ethyleneresponses in plants and plant materials by applying dicyclopropenecompounds and compositions thereof to plants. The invention furtherrelates to dicyclopropene compounds, enantiomers, stereoisomers andsalts thereof.

BACKGROUND OF THE INVENTION

Ethylene is known to mediate a variety of growth phenomena in plants.See generally Fritz et al. U.S. Pat. No. 3,879,188. This activity isunderstood to be achieved through a specific ethylene receptor inplants. Many compounds other than ethylene interact with this receptor:some mimic the action of ethylene; while others prevent ethylene frombinding and thereby counteract its action.

Many compounds that block the action of ethylene do so by binding to theethylene binding site. Unfortunately, they often diffuse from thebinding site over a period of several hours. See E. Sisler and C. Wood,Plant Growth Reg. 7, 181-191 (1988). These blocking compounds may beused to counteract ethylene action. However, a problem with suchcompounds is that exposure must be continuous if the effect is to lastfor more than a few hours.

Photoaffinity labeling has been used in biological studies to labelbinding sites in a permanent manner—usually by generating a carbene ornitrene intermediate. Such intermediates are generally reactive andreact rapidly and indiscriminately with many compositions. A compoundalready bound, however, would react mostly with the binding site. In apreliminary study, it was shown that cyclopentadiene was an effectiveblocking agent for ethylene binding. See E. Sisler et al., Plant GrowthReg. 9, 157-164 (1990). Methods of combating the ethylene response inplants with diazocyclopentadiene and derivatives thereof are describedin U.S. Pat. No. 5,100,462 to Sisler et al. U.S. Pat. No. 5,518,988 toSisler et al. describes the use of cyclopropenes having a C₁ to C₄ alkylgroup to block the action of ethylene.

Notwithstanding these efforts, however, there remains a need in the artfor additional methods providing improved plant maturation anddegradation regulation as well as those for counteractingethylene-induced processes in agricultural produce and/or horticulturalproducts.

SUMMARY OF THE INVENTION

The present invention includes dicyclopropene compounds of Formula I:

wherein:

m and n are independently an integer from 0 to 4;

R₁ and R₂ are independently C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl or C₂-C₂₀alkynyl, wherein at least one of R₁ or R₂ is C₁-C₅ alkyl, C₂-C₅ alkenyl,or C₂-C₅ alkynyl; and

L is selected from the group consisting of a covalent linkage,phosphorus, oxygen, sulfur, C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀alkynyl, C₃-C₈ cycloalkyl, heterocyclyl and aryl, or

an enantiomer, stereoisomer or a salt thereof.

In some embodiments, the compound has the following structure:

In particular embodiments, the compound has the following structure:

Embodiments of the present invention further provide compositionsincluding: (a) at least one of a compound of Formula I; and (b) anadjuvant, such as an agriculturally acceptable carrier.

The present invention further includes methods of inhibiting ethyleneresponses in plants and plant materials. Methods include inhibiting anethylene response in a plant, including applying to the plant aneffective ethylene response-inhibiting amount of a compound of Formula Ior a composition including at least one of a compound of Formula I; and(b) an adjuvant. In some embodiments, the compounds include those havingthe following structure:

Application of the compounds to a plant may be carried out by contactingthe plant to a gaseous or salt form of the compound or a mixturethereof, contacting the plant with a solid including the compound,applying a spray including the compound, dipping the plant in acomposition including the compound, and addition of the compound to acontainer containing the plant. Additionally, compounds of the presentinvention can be applied in an open or closed system. In particularembodiments, compounds of the present invention can be used outside, forexample, on field crops or landscape plants.

Embodiments of the present invention further provide methods ofprolonging the life of a cut flower or fresh produce, including applyingto the cut flower or fresh produce an effective life-prolonging amountof the dicyclopropene compounds described herein.

Aspects of the present invention may result in the prolongation ofstorability and shelf life of produce, such as fruits and vegetables,extension of the storage and vase life of cut flowers, extension of theharvest timing for field crops and/or prolongation of life of landscapeplants.

According to further aspects of the present invention, the compoundsdescribed herein are useful to provide protection against ethyleneregulated processes in vascular plants.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Effect of 1,6-dicyclopropenyl-hexane on etiolated plea plantgrowth.

DETAILED DESCRIPTION

Ethylene receptors are thought to form higher-order clusters composed ofreceptor dimer subunits. The receptor dimers can influence the signalingstates of neighboring dimers through direct contact. Accordingly,transmitters from many receptors may be altered by a singleligand-binding event. Dicyclopropene compounds can be involved incross-linking in ethylene receptor clusters. The compounds disclosedherein may exhibit significant anti-ethylene activity. In someembodiments, the compounds can be volatile, work efficiently atdifferent temperatures, active at 0.3 nL L⁻¹ when applied as a gasand/or protect fruits from ethylene for up to about 42 days.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Further, all publications, U.S.patent applications, U.S. patents and other references cited herein areincorporated by reference in their entireties.

The present invention can be practiced based upon the disclosuredescribed herein, in light of the knowledge of persons skilled in theart, and in light of the information set forth in U.S. Pat. No.6,365,549; U.S. Pat. No. 6,194,350; and U.S. Pat. No. 5,518,988. Thedisclosures of all of which are incorporated by reference herein intheir entirety.

Dicyclopropene compounds that may be used to carry out the presentinvention may be prepared by using various methods known to thoseskilled in the art. For example, as described by Baird et al. inPreparation and Lithiation of 1-Halogenocyclopropenes, J. CHEM. SOC.PERKIN TRANS. 11845-53 (1986). Additionally, dicyclopropenes can beprepared using methods described by N. I. Yakushkina and I. G. Bolesovin Dehydrohalogenation of onohalogenocyclopropanes as a Method for theSynthesis of Sterically Screened Cyclopropenes, RUSSIAN J. OF ORGANICCHEM. 15:853-59 (1979).

Dicyclopropene compounds of the present invention include those ofFormula I:

wherein:

m and n are independently an integer from 0 to 4. R₁ and R₂ areindependently C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl or C₂-C₂₀ alkynyl, wherein atleast one of R₁ or R₂ is C₁-C₅ alkyl, C₂-C₅ alkenyl or C₂-C₅ alkynyl. Lis selected from the group consisting of a covalent linkage, phosphorus,oxygen, sulfur, magnesium, C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl,C₃-C₈ cycloalkyl, heterocyclyl and aryl. In some embodiments, n and mare independently 1 or 2. In other embodiments, n and m are each 0. Infurther embodiments, L is C₁-C₆, C₆, C₁-C₁₂, C₁₂, or C₄-C₁₀ alkyl, C₄-C₈cycloalkyl or C₃-C₈ cycloalkyl. In further embodiments, at least one ofR₁ or R₂ is an alkyl, alkenyl, or alkynyl substituted with at least onesubstituent selected from the group consisting of halogen, amino,alkoxy, carboxy, alkoxycarbonyl and hydroxy. In other embodiments, atleast one of the carbon atoms in at least one of R₁ or R₂ is replaced byat least one substituent selected from the group consisting of an ester,nitrile, amine, amine salt, acid, acid salt, an ester of an acid,hydroxy, and a heteroatom selected from the group consisting of oxygenand nitrogen. In some embodiments, at least one of R₁ or R₂ is hexyl,and in other embodiments, at least one of R₁ or R₂ is octyl.

According to aspects of the present invention, one end of L may attachto any one of position 1, 2 or 3 and the opposite end of L may attach toany position of 1′, 2′ or 3′. In particular embodiments, the compoundhas the following structure:

According to embodiments of the present invention, the compound is1,6-dicyclopropenyl-hexane. In particular embodiments, the compound hasthe following structure:

Embodiments of the present invention further include enantiomers,stereoisomers and salts of the dicyclopropene compounds describedherein.

The terms “alkyl”, “alkenyl”, and “alkynyl”, as used herein, refer tolinear or branched alkyl, alkenyl or alkynyl substituents, which may beunsubstituted or substituted. Moreover, a range, such as C₁-C₆, meansthat the carbon chain can be C₁, C₂, C₃, C₄, C₅, or C₆ or any rangeinclusive of any of the values included in the range, for example,C₂-C₄. As used herein, the term “heterocyclyl”, heterocycle” or“heterocyclic” refer to saturated or partially unsaturated monocyclic,bicyclic or tricyclic groups having from 3 to 15 atoms, in someinstances 3 to 7, with at least one heteroatom in at least one of therings. As used herein, “aryl” refers to an aromatic group in a single orfused carbocyclic ring system having from 6 to 15 ring atoms, in someinstances 6 to 10, and includes substituted aromatic groups. Examples ofaryl groups include, but are not limited to, phenyl, 1-naphthyl,2-naphthyl and benzyl. As used herein, the term “halogen”, “halo” or“halide” refers to fluoro, fluorine or fluoride, chloro, chlorine orchloride, bromo, bromine or bromide, and iodo, iodine or iodide,accordingly.

Embodiments of the present invention further include a compositioncomprising, consisting essentially of or consisting of (a) at least oneof a compound of Formula I:

wherein m and n are independently an integer from 0 to 4; R₁ and R₂ areindependently C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl or C₂-C₂₀ alkynyl, wherein atleast one of R₁ or R₂ is an unsubstituted or substituted C₁-C₅ alkyl,C₂-C₅ alkenyl, or C₂-C₅ alkynyl; L is selected from the group consistingof a covalent linkage, phosphorus, oxygen, sulfur, magnesium, C₁-C₂₀alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl, C₃-C₈ cycloalkyl, heterocyclyland aryl, or an enantiomer, stereoisomer or a salt thereof; and (b) anacceptable adjuvant such as an agriculturally acceptable carrier.

Agricultural compositions including the dicyclopropene compoundsdescribed herein are also encompassed by the invention. In someembodiments, the compositions include 0.005% to 99%, by weight; in otherembodiments 1% to 95%, by weight; in further embodiments 2% to 90%, byweight; in still further embodiments 3% to 80%, by weight; and in someembodiments, 4% to 70%, by weight, of the active compounds of thepresent invention. As used herein, all percentages are percent by weightand all parts are parts by weight, unless otherwise specified, and areinclusive and combinable. All ratios are by weight and all ratio rangesare inclusive and combinable. All molar ranges are inclusive andcombinable.

These compositions may include one or more adjuvants, such as, forexample, carriers, extenders, binders, lubricants, surfactants and/ordispersants, wetting agents, spreading agents, dispersing agents,stickers, adhesives, defoamers, thickeners, and emulsifying agents. Suchadjuvants commonly used in the art can be found in the John W.McCutcheon, Inc. publication Detergents and Emulsifiers, Annual, AlluredPublishing Company, Ridgewood, N.J., U.S.A. The term “agriculturallyacceptable carrier” refers to adjuvants that are ordinarily used inagricultural formulation technology.

Numerous organic solvents may be used as carriers for the activecompounds of the present invention, e.g., hydrocarbons such as hexane,benzene, toluene, xylene, kerosene, diesel oil, fuel oil and petroleumnaphtha, ketones such as acetone, methyl ethyl ketone and cyclohexanone,chlorinated hydrocarbons such as carbon tetrachloride, esters such asethyl acetate, amyl acetate and butyl acetate, ethers, e.g., ethyleneglycol monomethyl ether and diethylene glycol monomethyl ether,alcohols, e.g., ethanol, methanol, isopropanol, amyl alcohol, ethyleneglycol, propylene glycol, butyl carbitol acetate and glycerine.

Mixtures of water and organic solvents, either as solutions oremulsions, can also be employed as inert carriers for the activecompounds.

The active compounds of the present invention may also include adjuvantsor carriers such as talc, pyrophyllite, synthetic fine silica,attapulgus clay (attaclay), kieselguhr, chalk, diatomaceous earth, lime,calcium carbonate, bentonite, fuller's earth, cottonseed hulls, wheatflour, soybean flour pumice, tripoli, wood flour, walnut shell flour,redwood flour and lignin.

It may be desirable to incorporate a wetting agent in the compositionsof the present invention. Such wetting agents may be employed in boththe solid and liquid compositions. The wetting agent can be anionic,cationic or nonionic in character.

Typical classes of wetting agents include alkyl sulfonate salts,alkylaryl sulfonate salts, alkyl sulfate salts, alkylamide sulfonatesalts, alkylaryl polyether alcohols, fatty acid esters of polyhydricalcohols and the alkylene oxide addition products of such esters, andaddition products of long chain mercaptans and alkylene oxides. Typicalexamples of such wetting agents include the sodium alkylbenzenesulfonates having 10 to 18 carbon atoms in the alkyl group, alkylphenolethylene oxide condensation products, e.g., p-isooctylphenol condensedwith 10 ethylene oxide units, soaps, e.g., sodium stearate and potassiumoleate, sodium salt of propylnaphthalene sulfonic acid(di-2-ethylhexyl), ester of sodium sulfosuccinic acid, sodium laurylsulfate, sodium stearate and potassium oleate, sodium salt of thesulfonated monoglyceride of coconut fatty acids, sorbitan, sesquioleate,lauryl trimethyl ammonium chloride, octadecyl trimethyl ammoniumchloride, polyethylene glycol lauryl ether, polyethylene esters of fattyacids and rosin acids (e.g., Ethofat® 7 and 13, commercially availablefrom Akzo Nobel Chemicals, Inc. of Chicago, Ill.), sodiumN-methyl-N-oleyltaurate, Turkey Red oil, sodium dibutylnaphthalenesulfonate, sodium lignin sulfonate (Marasperse® N, commerciallyavailable from LignoTech USA of Rothschild, Wis.), polyethylene glycolstearate, sodium dodecylbenzene sulfonate, tertiary dodecyl polyethyleneglycol thioether, long chain ethylene oxide-propylene oxide condensationproducts (e.g., Pluronic® 61 (molecular weight 1,000) commerciallyavailable from BASF of Mount Olive, N.J.), sorbitan sesquioleate,polyethylene glycol ester of tall oil acids, sodium octylphenoxyethoxyethyl sulfate, polyoxyethylene (20) sorbitan monolaurate(Tween® 20, commercially available from ICI Americas Inc. of Wilmington,Del.) tris(polyoxyethylene)sorbitan monostearate (Tween® 60,commercially available from ICI Americas Inc. of Wilmington, Del.), andsodium dihexyl sulfosuccinate. Solid, liquid, and gaseous formulationscan be prepared by various conventional procedures. Thus, the activeingredient, in finely divided form if a solid, may be tumbled togetherwith finely divided solid carrier. Alternatively, the active ingredientin liquid form, including mixtures, solutions, dispersions, emulsionsand suspensions thereof, may be admixed with a solid carrier in finelydivided form. Furthermore, the active ingredient in solid form may beadmixed with a liquid carrier to form a mixture, solution, dispersion,emulsion, suspension or the like.

Embodiments of the present invention further include methods ofinhibiting an ethylene response in a plant, comprising, consistingessentially of or consisting of applying to the plant an effectiveethylene response-inhibiting amount of at least one compound of FormulaI:

wherein m and n are independently an integer from 0 to 4; R₁ and R₂ areindependently C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl or C₂-C₂₀ alkynyl, wherein atleast one of R₁ or R₂ is C₁-C₅ alkyl, C₂-C₅ alkenyl or C₂-C₅ alkynyl;and L is selected from the group consisting of a covalent linkage,phosphorus, oxygen, sulfur, magnesium, C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl,C₂-C₂₀ alkynyl, C₃-C₈ cycloalkyl, heterocyclyl and aryl, or anenantiomer, stereoisomer or a salt thereof.

In particular embodiments, the compound has the following structure:

The active compounds of the present invention can be applied to plantsby various suitable means. For example, an active compound may beapplied alone in gaseous, liquid, or solid form or a mixture of anycombination thereof by contacting the compound with the plant to betreated. Additionally, the active compound may be converted to the saltform, and then applied to the plants. Alternatively, compositionscontaining one or more active compounds of the present invention may beformed. The compositions may be applied in gaseous, liquid, or solidform or a mixture of any combination thereof by contacting thecomposition with the plant to be treated. Such compositions may includean inert carrier. Suitable solid carriers include dusts. Similarly, whenin gaseous form, the compound may be dispersed in an inert gaseouscarrier to provide a gaseous solution. The active compound may also besuspended in a liquid solution such as an organic solvent or an aqueoussolution that may serve as the inert carrier. Solutions containing theactive compound may be heterogeneous or homogeneous and may be ofvarious forms including mixtures, dispersions, emulsions, suspensionsand the like.

The active compounds and compositions thereof can also be applied asaerosols, e.g., by dispersing them in air using a compressed gas suchas, for example, nitrogen, carbon dioxide, dichlorodifluoromethane,trichlorofluoromethane, or other halocarbons.

Accordingly, in some embodiments, methods of the present invention canbe carried out by contacting a plant to a gaseous form of adicyclopropene compound described herein, spraying a plant with asolution including the dicyclopropene compounds described herein and/orcontacting a plant to a solid including the dicyclopropene compoundsdescribed herein.

The present invention can be employed to modify a variety of differentethylene responses. Ethylene responses may be initiated by eitherexogenous or endogenous sources of ethylene. Ethylene responses include,for example, the ripening and/or senescence of flowers, fruits andvegetables, abscission of foliage, flowers and fruit, the shortening ofthe life of ornamentals such as potted plants, cut flowers, shrubbery,and dormant seedlings, in some plants (e.g., pea) the inhibition ofgrowth, and in other plants (e.g., rice) the stimulation of growth.Additional ethylene responses or ethylene-type responses that may beinhibited by active compounds of the present invention include, but arenot limited to, auxin activity, inhibition of terminal growth, controlof apical dominance, increase in branching, increase in tillering,changing bio-chemical compositions of plants (such as increasing leafarea relative to stem area), abortion or inhibition of flowering andseed development, lodging effects, stimulation of seed germination andbreaking of dormancy, and hormone or epinasty effects. Thus, in someembodiments, the dicyclopropene compounds described herein inhibit oneor more of ripening or senescence of flowers, fruits, and vegetables;abscission of foliage, flowers, and fruit; the shortening of life ofornamental plants, cut flowers, shrubbery, seeds, or dormant seedlings;inhibition of growth; stimulation of growth; auxin activity; inhibitionof terminal growth; control of apical dominance; increase in branching;increase in tillering; changing the morphology of plants; modifying thesusceptibility to plant pathogens such as fungi; changing bio-chemicalcompositions; inducing pest resistance; abortion or inhibition offlowering or seed development; lodging effects; stimulation of seedgermination; breaking of dormancy; hormone effects; and epinastyeffects. In some embodiments, the plant is a whole plant and or anyportions thereof, a field crop, landscape plant, potted plant, cutflower, or harvested fruit or vegetable.

In some embodiments the ethylene response is fruit ripening, vegetableripening, and/or flower senescence.

In some embodiments, the compounds can be applied in a closed or opensystem. In some embodiments, the compounds can be used as a gas in aclosed system, for example, indoors or applied to a plant in a containeror in a greenhouse. In other embodiments, the compounds can be used asalt, which can be used, for example, in a spray, in an open system,such as outdoors, for example, on field crops or landscape plantsincluding flowers.

The term “plant” is used in a generic sense herein, and includeswoody-stemmed plants such as trees and shrubs. Plants to be treated bythe methods described herein include whole plants and any portionsthereof, field crops, landscape plants, potted plants, cut flowers(stems and flowers), and harvested fruits and vegetables. Accordingly,plants include agricultural produce, such as fresh produce, andlandscape plants such as trees, shrubs, potted plants and ornamentalplants.

Plants treated with the compounds or compositions and by the methods ofthe present invention are preferably treated with a non-phytotoxicamount of the active compound.

Vegetables that may be treated by the method of the present invention toinhibit an ethylene response, such as ripening and/or senescence,include leafy green vegetables such as lettuce (e.g., Lactuea sativa),spinach (Spinaca oleracea), and cabbage (Brassica oleracea), variousroots, such as potatoes (Solanum tuberosum) and carrots (Daucus), bulbs,such as onions (Allium sp.), herbs, such as basil (Ocimum basilicum),oregano (Origanum vulgare), dill (Anethum graveolens), as well assoybean (Glycine max), lima beans (Phaseolus limensis), peas (Lathyrusspp.), corn (Zea mays), broccoli (Brassica oleracea italica),cauliflower (Brassica oleracea botrytis), and asparagus (Asparagusofficinalis).

Fruits which may be treated by the method of the present invention toinhibit an ethylene response, such as ripening, include tomatoes(Lycopersicon esculentum), apples (Malus domestica), bananas (Musasapientum), pears (Pyrus communis), papaya (Carica papaya), mangoes(Mangifera indica), peaches (Prunus persica), apricots (Prunusarmeniaca), nectarines (Prunus persica nectarina), oranges (Citrus sp.),lemons (Citrus limonia), limes (Citrus aurantifolia), grapefruit (Citrusparadisi), tangerines (Citrus nobilis deliciosa), kiwi (Actinidiachinenus), melons such as cantaloupe (C. cantalupensis) and musk melon(C. melo), pineapple (Aranas comosus), persimmon (Diospyros sp.),various small fruits including berries such as strawberries (Fragaria),blueberries (Vaccinium sp.) and raspberries (e.g., Rubus ursinus), greenbeans (Phaseolus vulgaris), members of the genus Cucumis such ascucumber (C. sativus), and avocados (Persea americana).

Ornamental plants that may be treated by the method of the presentinvention to inhibit an ethylene response, such as senescence and/orshortening of flower life and, thus prolong flower life and appearance(e.g., delay wilting), include potted ornamentals, and cut flowers.Potted ornamentals and cut flowers which may be treated with the presentinvention include azalea (Rhododendron spp.), hydrangea (Macrophyllahydrangea), hybiscus (Hibiscus rosasanensis), snapdragons (Antirrhinumsp.), poinsettia (Euphorbia pulcherima), cactus (e.g. Cactaceaeschlumbergera truncata), begonias (Begonia sp.), roses (Rosa spp.),tulips (Tulipa sp.), daffodils (Narcissus spp.), dandelions (Taraxacumoffinale), petunias (Petunia hybrida), carnation (Dianthuscaryophyllus), lily (e.g., Lilium sp.), gladiolus (Gladiolus sp.),alstroemeria (Alstoemeria brasiliensis), anemone (e.g., Anemone blanda),columbine (Aquilegia sp.), aralia (e.g., Aralia chinensis), aster (e.g.,Aster carolinianus), bougainvillea (Bougainvillea sp.), camellia(Camellia sp.), bellflower (Campanula sp.), cockscomb (celosia sp.),falsecypress (Chamaecyparis sp.), chrysanthemum (Chrysanthemum sp.),clematis (Clematis sp.), cyclamen (Cyclamen sp.), freesia (e.g., Freesiarefracta), and orchids of the family Orchidaceae.

Plants which may be treated by the method of the present invention toinhibit an ethylene response, such as abscission of foliage, flowers andfruit, include cotton (Gossypium spp.), apples, pears, cherries (Prunusavium), pecans (Carva illinoensis), grapes (Vitis vinifera), olives(e.g. Vitis vinifera and Olea europaea), coffee (Coffea arabica),snapbeans (Phaseolus vulgaris), and weeping fig (ficus benjamina), aswell as dormant seedlings such as various fruit trees including apple,ornamental plants, shrubbery, and tree seedlings. In addition, shrubberywhich may be treated according to the present invention to inhibit anethylene response, such as abscission of foliage, include privet(Ligustrum sp.), photinea (Photinia sp.), holly (Ilex sp.), ferns of thefamily Polypodiaceae, schefflera (Schefflera sp.), aglaonema (Aglaonemasp.), cotoneaster (Cotoneaster sp.), barberry (Berberis sp.), waxmyrtle(Myrica sp.), abelia (Abelia sp.), acacia (Acacia sp.) and bromeliadesof the family Bromeliaceae.

Field crops which may be treated by the methods of the present inventioninclude a plurality of, or at least more than one, tree, bush, shrub,plant, etc. including the vegetables, fruits, ornamental plants andplants discussed herein.

Active compounds of the present invention have proven to be unexpectedlypotent inhibitors of ethylene action on plants, fruits and vegetables,even when applied at low concentrations and varying temperatures. Amongother things, compounds of the present invention may result in a longerperiod of insensitivity to ethylene than compounds found in the priorart. This longer period of insensitivity may occur even when compoundsof the present invention are applied at a lower concentration thanprevious compounds, at varying temperatures and/or when applied as a gasor spray.

The present invention is explained in greater detail in the followingnon-limiting examples. In these examples, μl means microliters; ml meansmilliliters; nl means nanoliters; I means liters; cm means centimeters;and temperatures are given in degrees Celsius.

Example 1 General Procedure of the Preparation of DicyclopropeneCompounds

The dicyclopropene compounds can be prepared by using a modifiedprocedure of Al Dulayymi et al. (1996 and 1997). All appropriatestarting materials are either commercially available or can be readilyprepared by one of ordinary skill in the art. The appropriate startingmaterial can react with bromoform in the presence of 50% NaOH andsubsequently react with methyllithium to provide the desireddicyclopropene compounds. (See Al Dulayymi J. R., et al., Structurebased interference with insect behaviour-Cyclopropenes analogs ofpheromones containing Z-Alkenes, Tetrahedron, 52, 12509-12520 (1996); AlDulayymi A. R., et al., Simple four and five carbon cyclopropane andcyclopropene synthetic intermediates, Russian. J. Org. Chem., 33,798-816 (1997); Al Dulayymi J. R., et al., Synthesis of Putative ˜6-, 12and ˜15-Desaturase Inhibitors, Tetrahedron, 53, 1099-1110 (1997)).

Example 2 Preparation of 1,6-dicyclopropenyl-hexane

1,9-Decadiyne (CAS Registry Number: 1720-38-3) was used as a startingmaterial, and it was brominated to provide the intermediate2,9-dibromodeca-1,9-diene by using the procedure of Couseau, J,Synthesis, 805-806 (1980). Then the 2,9-dibromodeca-1,9-diene reactedwith bromoform and NaOH and subsequently reacted with methyllithium toprovide 1,6-dicylcopropenyl-hexane by using the procedure of Dulayymi, JR et al. Tetrahedron, 53, 1099-1110 (1997) and Dulayymi, J R et al.Tetrahedron, 52, 12509-12520, (1996).

Example 3 Effect of 1,6-dicyclopropenyl-hexane on Pea Plant Growth

1,6-dicyclopropenyl-hexane was synthesized and found to exhibitsignificant anti-ethylene activity as shown in FIG. 1. FIG. 1 (left)shows pea plants grown in the presence of 1 ppm of ethylene. FIG. 1(right) shows pea plants grown in the presence of both 1 ppm of ethyleneand 1,6-dicyclopropenyl-hexane. 1,6-dicyclopropenyl-hexane was shown tobe volatile, work efficiently at different temperatures, active at 0.3nL L⁻¹ when applied as a gas and/or protect bananas from ethyleneresponses for at least about 42 days.

The foregoing embodiments and examples are illustrative of the presentinvention and are not to be construed as limiting thereof. The inventionis defined by the following claims, with equivalents of the claims to beincluded therein.

That which is claimed is:
 1. A method of inhibiting an ethylene responsein a plant, comprising applying to the plant an effective ethyleneresponse-inhibiting amount of at least one compound of Formula I:

wherein: m and n are independently an integer from 0 to 4; R₁ and R₂ areindependently C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl or C₂-C₂₀ alkynyl, wherein atleast one of R₁ or R₂ is C₁-C₅ alkyl, C₂-C₅ alkenyl or C₂-C₅ alkynyl;and L is selected from the group consisting of a covalent linkage,phosphorus, oxygen, sulfur, C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀alkynyl, C₃-C₈ cycloalkyl, heterocyclyl and aryl, or an enantiomer,stereoisomer, salt or composition thereof.
 2. The method of claim 1,wherein the compound has the following structure:

wherein: m and n are independently an integer from 0 to 4; R₁ and R₂ areindependently C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl or C₂-C₂₀ alkynyl, wherein atleast one of R₁ or R₂ is C₁-C₅ alkyl, C₂-C₅ alkenyl or C₂-C₅ alkynyl;and L is selected from the group consisting of a covalent linkage,phosphorus, oxygen, sulfur, C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀alkynyl, C₃-C₈ cycloalkyl, heterocyclyl and aryl.
 3. The method of claim1, wherein the compound has the following structure:

wherein: m and n are independently an integer from 0 to 4; R₁ and R₂ areindependently C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl or C₂-C₂₀ alkynyl, wherein atleast one of R₁ or R₂ is C₁-C₅ alkyl, C₂-C₅ alkenyl or C₂-C₅ alkynyl;and L is selected from the group consisting of a covalent linkage,phosphorus, oxygen, sulfur, C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀alkynyl, C₃-C₈ cycloalkyl, heterocyclyl and aryl.
 4. The method of claim1, wherein the compound has the following structure:

wherein: m and n are independently an integer from 0 to 4; R₁ and R₂ areindependently C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl or C₂-C₂₀ alkynyl, wherein atleast one of R₁ or R₂ is C₁-C₅ alkyl, C₂-C₅ alkenyl or C₂-C₅ alkynyl;and L is selected from the group consisting of a covalent linkage,phosphorus, oxygen, sulfur, C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀alkynyl, C₃-C₈ cycloalkyl, heterocyclyl and aryl.
 5. The method of claim1, wherein n and m are independently 1 or
 2. 6. The method of claim 1,wherein n and m are each
 0. 7. The method of claim 1, wherein L is C₆alkyl.
 8. The method of claim 1, wherein at least one of R₁ or R₂ is analkyl, alkenyl, or alkynyl substituted with at least one substituentselected from the group consisting of halogen, amino, alkoxy, carboxy,alkoxycarbonyl and hydroxy.
 9. The method of claim 1, wherein at leastone of the carbon atoms in at least one of R₁ or R₂ is replaced by atleast one substituent selected from the group consisting of an ester,nitrile, amine, amine salt, acid, acid salt, an ester of an acid,hydroxy, and a heteroatom selected from the group consisting of oxygenand nitrogen.
 10. The method of claim 1, wherein at least one of R₁ orR₂ is hexyl.
 11. The method of claim 1, wherein at least one of R₁ or R₂is octyl.
 12. The method of claim 1, wherein application is carried outby contacting said plant to a gas of said compound.
 13. The method ofclaim 1, wherein application is carried out by contacting said plant toa salt of said compound.
 14. The method of claim 1, wherein applicationis carried out by spraying said plant with a solution comprising saidcompound.
 15. The method of claim 1, wherein application is carried outby contacting said plant to a solid comprising said compound.
 16. Themethod of claim 1, wherein application is carried by applying a spraycomprising said compound.
 17. The method of claim 1, wherein saidethylene response is one or more of ripening or senescence of flowers,fruits, and vegetables; abscission of foliage, flowers, and fruit; theshortening of life of ornamental plants, cut flowers, shrubbery, seeds,or dormant seedlings; inhibition of growth; stimulation of growth; auxinactivity; inhibition of terminal growth; control of apical dominance;increase in branching; increase in tillering; changing the morphology ofplants; modifying the susceptibility to plant pathogens such as fungi;changing bio-chemical compositions; inducing pest resistance; abortionor inhibition of flowering or seed development; lodging effects;stimulation of seed germination; breaking of dormancy; hormone effects;and epinasty effects.
 18. The method of claim 1, wherein said compoundcan be applied in a closed system.
 19. The method of claim 1, whereinsaid compound can be applied in an open system
 20. The method of claim1, wherein said plant is a whole plant or any portions thereof, a fieldcrop, landscape plant, potted plant, cut flower or harvested fruit orvegetable.
 21. A method of inhibiting an ethylene response in a plant,comprising applying to the plant an effective ethyleneresponse-inhibiting amount of compound having the following structure:

or a salt thereof.
 22. The method of claim 21, wherein application iscarried out by contacting said plant to a gas of said compound.
 23. Amethod of inhibiting an ethylene response in a plant grown in a fieldcrop, comprising applying to the field crop an effective ethyleneresponse-inhibiting amount of a spray formulation comprising at leastone compound of Formula I:

wherein: m and n are independently an integer from 0 to 4; R₁ and R₂ areindependently C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl or C₂-C₂₀ alkynyl, wherein atleast one of R₁ or R₂ is C₁-C₅ alkyl, C₂-C₅ alkenyl or C₂-C₅ alkynyl;and L is selected from the group consisting of a covalent linkage,phosphorus, oxygen, sulfur, C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀alkynyl, C₃-C₈ cycloalkyl, heterocyclyl and aryl, or an enantiomer,stereoisomer or a salt thereof.
 24. The method of claim 23, wherein saidethylene response is one or more of ripening or senescence of flowers,fruits, and vegetables; abscission of foliage, flowers, and fruit; theshortening of life of ornamental plants, cut flowers, shrubbery, seeds,or dormant seedlings; inhibition of growth; stimulation of growth; auxinactivity; inhibition of terminal growth; control of apical dominance;increase in branching; increase in tillering; changing the morphology ofplants; modifying the susceptibility to plant pathogens such as fungi;changing bio-chemical compositions; inducing pest resistance; abortionor inhibition of flowering or seed development; lodging effects;stimulation of seed germination; breaking of dormancy; hormone effects;and epinasty effects.
 25. A method of prolonging the life of a landscapeplant comprising applying to the landscape plant an effective ethyleneresponse-inhibiting amount of a spray formulation comprising at leastone compound of Formula I:

wherein: m and n are independently an integer from 0 to 4; R₁ and R₂ areindependently C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl or C₂-C₂₀ alkynyl, wherein atleast one of R₁ or R₂ is C₁-C₅ alkyl, C₂-C₅ alkenyl or C₂-C₅ alkynyl;and L is selected from the group consisting of a covalent linkage,phosphorus, oxygen, sulfur, C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀alkynyl, C₃-C₈ cycloalkyl, heterocyclyl and aryl, or an enantiomer,stereoisomer or a salt thereof.
 26. The method of claim 25, wherein thecompound has the following structure:

or an enantiomer, stereoisomer or a salt thereof.